My ideal planetary scope depends on weather conditions and how energetic (or not) I feel. That can be anything from my 10" Dob to my 70mm f/13 achromat. I have noticed that frequency of use is inversely proportional to aperture and hassle factor. YMMV

My ideal planetary scope depends on weather conditions and how energetic (or not) I feel. That can be anything from my 10" Dob to my 70mm f/13 achromat. I have noticed that frequency of use is inversely proportional to aperture and hassle factor. YMMV

Ed D

I hear that. If there's snow on the ground, then the TV101 (tripod) becomes the planet scope. If it's really cold, the instant set-up 8" f/6 Dob becomes ideal.

I have an 8” F9 reflector, and I agree that one f ratio less would have made the scope much more manageable.

My first Newtonian was an 8.5" F8. It would have been better on a Dob mount. The GEM was sturdy enough and views were excellent, but took too long to set up each night. I bought a C8 when moving to a smaller house.

The ideal planetary scope might not be ideal in all circumstances. One would think the larger the aperture the better. But I have often compared my Starmaster 16.5" with my Tec 180FL. There are times when the SM gives what I would call a better image of Jupiter where it is easier to see some of the festoons, but more often for whatever reason the Tec gives me the more pleasing image and with more detail. If the seeing is not really good then the SM can't reach its potential and seems to be more effected by the seeing blurring the detail. Other reasons could be due to insufficient cooling or my body heat. But whatever the reason I get views I enjoy more often in the Tec. And sometimes the image between the 2 is just different and I am glad I have both to view through. One may not necessarily be better than the other. One is cleaner but the other has more color, for example.

I view from my neighborhood where there are homes and so I may be getting the effects of roofs giving off heat. In other locations, I might get better results but it is far easier for me to view from my backyard.

I have been to a few star parties including ones at the grand canyon. I have rarely seen good views of the planets. It could be the seeing, it could be the collimation or lack of cooling. I have never had a good view from the larger dobs and I always ask if they collimated it and if they say yes I am still not sure how well. The 2 best views I have had over the years at star parties were from a Celestron Edge 14" of Saturn and a dob that had an unobstructed aperture mask again of Saturn. I was very surprised at this because many people say larger aperture is always better and masks won't help, but in this case, this scope was beating the other larger apertures by quite a bit. The seeing wasn't supporting the larger apertures or maybe they weren't collimated as well. I don't have enough experience to know but I did like the view from the masked scope the best. I would have liked to see what Saturn looked like in the scope without the mask but I didn't ask. The operator said the mask worked very well and it seemed to be doing its job for me.

With larger aperture, if you are patient you will get the detail over time. The detail will come and go. Some would rather see less detail more often than more detail but over hours of viewing. An example for me is the Alpine Valley Rille on the moon. I have seen it many times in my Tec but less often in the SM. When I did see it in the SM it was larger and brighter and easier to see but that was once. Same with the Plato craterlets. It is less often in the larger aperture that I get the views that I really like but when I do, they are brighter and the craterlets are easier to see.

All of the fine details in differences between scopes tend to blur, pun intended I guess, in comparison to seeing.

Honestly, until last winter, I never knew what good / great seeing really was. Now that I do know, I realize that at home on my best nights I'm seeing 50 percent of what I could be, and on most nights closer to 25 percent.

I used to think that because I was having a good night and enjoying views at 300-400x the seeing was fantastic. In reality, in absolute terms, it was more like a 6 / 10.

I had the good fortune of spending a couple of months last winter in southern Baja California, and night after night the seeing was essentially perfect, with the stars just hard little dots against the black sky. Even Sirius showed no sign of twinkling. I had my 16' travel dob with me and the highest magnification I could get with the eyepieces I had was about 500x, but was no where near to maxing out the seeing.

I guess this is the kind of seeing I see described from South Florida at times and some other tropical / high altitude locations, but for me it was the first time i had the opportunity to experience it, and it made me realize that even with my "optimized" planetary scope how little I am really seeing.

Ii know this isn't exactly on topic with "best planetary scope" discussion of the month, but I guess the point I'm trying to make is if you live where the seeing is poor, instead of spending a fortune on a high end scope, think about getting a good scope and spending some of the money on traveling somewhere with incredible seeing, such as the Winter Star Party or elsewhere for a trip and getting the views of your life. Great planetary views are about more than just the scope.

For portability and general user friendliness, an 8 inch F6 solid tube can't be beat, if the mirror is good. Collimation is easy, goes in smaller cars, and if planets are not playing nice, you can get gratification on other objects.

All of the fine details in differences between scopes tend to blur, pun intended I guess, in comparison to seeing.

Honestly, until last winter, I never knew what good / great seeing really was. Now that I do know, I realize that at home on my best nights I'm seeing 50 percent of what I could be, and on most nights closer to 25 percent.

I used to think that because I was having a good night and enjoying views at 300-400x the seeing was fantastic. In reality, in absolute terms, it was more like a 6 / 10.

I had the good fortune of spending a couple of months last winter in southern Baja California, and night after night the seeing was essentially perfect, with the stars just hard little dots against the black sky. Even Sirius showed no sign of twinkling. I had my 16' travel dob with me and the highest magnification I could get with the eyepieces I had was about 500x, but was no where near to maxing out the seeing.

I guess this is the kind of seeing I see described from South Florida at times and some other tropical / high altitude locations, but for me it was the first time i had the opportunity to experience it, and it made me realize that even with my "optimized" planetary scope how little I am really seeing.

Ii know this isn't exactly on topic with "best planetary scope" discussion of the month, but I guess the point I'm trying to make is if you live where the seeing is poor, instead of spending a fortune on a high end scope, think about getting a good scope and spending some of the money on traveling somewhere with incredible seeing, such as the Winter Star Party or elsewhere for a trip and getting the views of your life. Great planetary views are about more than just the scope.

Well, I'm not spending on high-end stuff. Just a used 8" f/8 and a tracking mount. I consider 250x to be a respectable night. I might get more with the 12.5", but no tracking and the distraction of hand tracking the scope detracts from the detail. On good nights, which are more common than one might suppose, I could probably push an 8" to 350x. Good stuff.

All of the fine details in differences between scopes tend to blur, pun intended I guess, in comparison to seeing.

Honestly, until last winter, I never knew what good / great seeing really was. Now that I do know, I realize that at home on my best nights I'm seeing 50 percent of what I could be, and on most nights closer to 25 percent.

I used to think that because I was having a good night and enjoying views at 300-400x the seeing was fantastic. In reality, in absolute terms, it was more like a 6 / 10.

I had the good fortune of spending a couple of months last winter in southern Baja California, and night after night the seeing was essentially perfect, with the stars just hard little dots against the black sky. Even Sirius showed no sign of twinkling. I had my 16' travel dob with me and the highest magnification I could get with the eyepieces I had was about 500x, but was no where near to maxing out the seeing.

I guess this is the kind of seeing I see described from South Florida at times and some other tropical / high altitude locations, but for me it was the first time i had the opportunity to experience it, and it made me realize that even with my "optimized" planetary scope how little I am really seeing.

Ii know this isn't exactly on topic with "best planetary scope" discussion of the month, but I guess the point I'm trying to make is if you live where the seeing is poor, instead of spending a fortune on a high end scope, think about getting a good scope and spending some of the money on traveling somewhere with incredible seeing, such as the Winter Star Party or elsewhere for a trip and getting the views of your life. Great planetary views are about more than just the scope.

Yes, average/good/great/excellent seeing are very relative to the observer's experience. I was spoiled by relatively good seeing in my early observing years, and considered it normal. There were plenty of nights of poor or average seeing as well, but I didn't appreciate how much better it was on a very good night than the best some others get. And the places I was observing from weren't renowned for their seeing, liked Florida or some of the pacific coastal sites that routinely get very steady air. However, much of the South and gulf coast gets some of this benefit.

Having moved to a location that never gives me the same steadiness of sky (at least not for 3 years running), I now understand things that people have often said from other regions about what their typical seeing limits were. I thought they were exaggerating before I had more experience with it first hand. I finally appreciate why they didn't pursue the type of doubles I had, the types of planetary detail I took for granted, etc. Before I had assumed that while rock steady 1/4 arc second nights were rare, I assumed that they did happen periodically a handful of times each year, even in locations where good seeing was infrequent.

I formerly believed that on "average" nights, enough time waiting at the eyepiece would reward with a few seconds of very good seeing for planetary/double starts, etc...hey, it worked where I lived at the time. What I have learned since is that there are places where "average" is poor, so much "faster" in frequency of the seeing undulations, that those moments only come on nights of good seeing. Sitting around for an hour or two waiting for moment of crispness is a fool's errand in fast seeing...and fast seeing can be "average" for a location. Lucky imaging can capture the shorter time slices, but the eye cannot. The speed of the seeing is key from what I have noticed. Seeing doesn't have to be all that steady if the variation is slow enough. In slow seeing the sharper moments last long enough and are frequent enough that one can make use of them. One can even chase them with the focuser in larger aperture.

It has been a real eye opener to me (pun intended, but quite literally true.) Those blessed with better seeing often do not realize how unusual or even alien it is to others who do not have experience with it. When I was first observing here and the seeing seemed average to me, other club members were raving about how great it was. I was perplexed wondering if my collimation or thermal management was holding me back, so I would wander over to their scopes to see if they were putting up better/steadier images. Spoiler alert, they were limited to about the same magnifications and for a given aperture about the same level of detail that I was. We simply had different expectations based on our experiences. That was a temporary relief, but a long term disappointment since it meant that there was nothing in my control that I could readily improve.

I can get a relative sense of other CN members' typical seeing by the way they describe more challenging planetary features that appear with successive levels of improvement in seeing (assuming one has the aperture to make use of it.) There are some very skilled observers, but there is only so far skill/patience or even perfect optics can take someone if the seeing is not cooperative.

While the seeing here is disappointing, the number of clear nights each year, and access to very dark skies is incredible. So I don't bother with detailed planetary sketches anymore, I rarely chase very difficult doubles, and instead am surveying thousands of the faintest galaxies I can detect.

Yes, average/good/great/excellent seeing are very relative to the observer's experience. I was spoiled by relatively good seeing in my early observing years, and considered it normal. There were plenty of nights of poor or average seeing as well, but I didn't appreciate how much better it was on a very good night than the best some others get. And the places I was observing from weren't renowned for their seeing, liked Florida or some of the pacific coastal sites that routinely get very steady air. However, much of the South and gulf coast gets some of this benefit.

Having moved to a location that never gives me the same steadiness of sky (at least not for 3 years running), I now understand things that people have often said from other regions about what their typical seeing limits were. I thought they were exaggerating before I had more experience with it first hand. I finally appreciate why they didn't pursue the type of doubles I had, the types of planetary detail I took for granted, etc. Before I had assumed that while rock steady 1/4 arc second nights were rare, I assumed that they did happen periodically a handful of times each year, even in locations where good seeing was infrequent.

I formerly believed that on "average" nights, enough time waiting at the eyepiece would reward with a few seconds of very good seeing for planetary/double starts, etc...hey, it worked where I lived at the time. What I have learned since is that there are places where "average" is poor, so much "faster" in frequency of the seeing undulations, that those moments only come on nights of good seeing. Sitting around for an hour or two waiting for moment of crispness is a fool's errand in fast seeing...and fast seeing can be "average" for a location. Lucky imaging can capture the shorter time slices, but the eye cannot. The speed of the seeing is key from what I have noticed. Seeing doesn't have to be all that steady if the variation is slow enough. In slow seeing the sharper moments last long enough and are frequent enough that one can make use of them. One can even chase them with the focuser in larger aperture.

It has been a real eye opener to me (pun intended, but quite literally true.) Those blessed with better seeing often do not realize how unusual or even alien it is to others who do not have experience with it. When I was first observing here and the seeing seemed average to me, other club members were raving about how great it was. I was perplexed wondering if my collimation or thermal management was holding me back, so I would wander over to their scopes to see if they were putting up better/steadier images. Spoiler alert, they were limited to about the same magnifications and for a given aperture about the same level of detail that I was. We simply had different expectations based on our experiences. That was a temporary relief, but a long term disappointment since it meant that there was nothing in my control that I could readily improve.

I can get a relative sense of other CN members' typical seeing by the way they describe more challenging planetary features that appear with successive levels of improvement in seeing (assuming one has the aperture to make use of it.) There are some very skilled observers, but there is only so far skill/patience or even perfect optics can take someone if the seeing is not cooperative.

While the seeing here is disappointing, the number of clear nights each year, and access to very dark skies is incredible. So I don't bother with detailed planetary sketches anymore, I rarely chase very difficult doubles, and instead am surveying thousands of the faintest galaxies I can detect.

Yeah, I guess we'reaking a virtue out of necessity. I've got a lot of clouds, but the seeing is often decent if not great. So, planets. Once or twice per year I bring the 12.5" to Cherry Springs PA for galaxies etc.

I think a 12.5" F/6 would be my ideal planet / all around scope. Also eyeballing the 15" F/5-F/5.2 (highest I could get without needing a ladder). Keeping both of these in mind for when I can build/buy a dream scope.

Ii know this isn't exactly on topic with "best planetary scope" discussion of the month, but I guess the point I'm trying to make is if you live where the seeing is poor, instead of spending a fortune on a high end scope, think about getting a good scope and spending some of the money on traveling somewhere with incredible seeing, such as the Winter Star Party or elsewhere for a trip and getting the views of your life. Great planetary views are about more than just the scope.

I wrote in my first post to this thread:

My thinking:

"- In getting good planetary views, seeing is the number one priority. It all starts with the seeing. One wants a scope of sufficient aperture than on a good night, it is not limited by it's aperture."

I am often blessed with very good seeing here along the coast in San Diego and not so good seeing in the mountains east of here so I am a pretty good idea of the range of possibilities.

I have said this before:

There are really two types of planetary scopes:

- Scopes that make the best of a near optimal situation.. These are large scopes that can take advantage of excellent seeing. The seeing is steady, no need to wait for that one moment when it all comes together, it's just a question of looking..

Of course at age 70, one doesn't necessarily wait for that excellent seeing, one waits for the floaters to pass by.

- Scope that make the best of a bad situation. In some locations poor seeing the SOP and planetary observing means waiting for the one moment of clarity. Such locations often have rather severe weather and a smaller scope that is more thermally stable and is always ready for those few fleeting moments is a better choice than a larger scope that is more finicky.

While refractors have come and gone in my collection I have always had Newtonian.

So it pains me to say this, but the ideal planet scope is a refractor.

Well, I'm a life-long Refractor Guy, but my ideal planet scope would be a well-made 10" (12.5" preferred) Cassegrain, permanently mounted in an observatory. My 6" & 4" Casses have shown me the benefits of this design for larger apertures than my 6" F8 APO -- uses mirrors like a Newt, but the focus is at the rear like a frac.

While refractors have come and gone in my collection I have always had Newtonian.

So it pains me to say this, but the ideal planet scope is a refractor.

Well, I'm a life-long Refractor Guy, but my ideal planet scope would be a well-made 10" (12.5" preferred) Cassegrain, permanently mounted in an observatory. My 6" & 4" Casses have shown me the benefits of this design for larger apertures than my 6" F8 APO -- uses mirrors like a Newt, but the focus is at the rear like a frac.

Well Cassegrains do save a lot of space and they don't have weirdly positioned focusers.

A Cass with sufficient back focus & a rotating focuser (like the 4" F15 I built using a vintage Edmund/3B mirror set) is great for comfortable seated observing. An 8" F7 Newtonian on a GEM is a good compromise for me, provided it has rotating rings, or is easier to turn in hinged rings than my RV-6 -- a shorter & cheaper scope, too than a Cass.

On nights when I have maybe an hour to observe, I'm not going to haul out my APM 152ED F8 APO + pedestal GEM, not while I have these two 6" Newtonians on Polaris mounts:

Well Cassegrains do save a lot of space and they don't have weirdly positioned focusers.

I have a friend who lives just North of Boston and its light dome - so he has concentrated on 'planets' when at home, mostly imaging, but visual too. His seeing is often 'fair', but sometimes very good thanks to being only a mile or so from the Atlantic I guess.

He started with a highly modified C-11 (tube cut-outs, etc) - but has moved on to a home-made truss DK Cass - which I believe is 16 or 18 inches - optics made by Royce. Since the scope is a "planets only special" he was not interested in correcting the DK outer-field aberrations. He also has a 5-inch class Tak APO, which he uses to image/observe Mercury and Venus during the daytime.

One of his "secrets" is using a ZWO Atmospheric Dispersion Corrector - and when imaging, a high-quality cooled monochrome camera. The high-end camera is capable of extremely short exposures, which when combined with the bright images of the big scope, give a reasonable chance to 'beat the seeing'.

I have a ZWO ADC - but my seeing is usually awful, so I've not had too much success with it. However, at Stellafane this year, we were looking at Jupiter with my Obsession 20 F/5 - very late night - and he insisted on getting his ADC to try. I did not have a 1.25" eyepiece that would come to focus, but we borrowed one - plus a 1.25" Barlow - and ended up at some pretty high power. To my amazement - the view with the ADC, once properly 'dialed in' was noticeably improved! This opinion was shared by several long-experience observers still up at a very late hour.

One post here mentions using an Obsession 20 as a 'planetary scope'! A view of Mars thru one owned by some friends is the reason I bought one used the very next week! The big Dob was doing an obviously better job on Mars that night than a C-14 and two Astro-Physics 6-inch APOs (in the opinion of about a dozen experienced observers). I knew big Dob's were great deep sky scopes - but they kill planets too - under the right circumstances.

Another post mentions our poor Northeast seeing ( alas, true ) and Cherry Springs as a dark sky mecca - well I live some of the time within a reasonable 2.5 hour drive - so I've been there 12 or more nights per year for the last dozen years. On just 3 nights I have seen excellent seeing there - good enough to put 800x on a friend's 16" F/4.5 and to abandon those 14th mag galaxies from 3 AM until well in the dawn - fascinated by all the detail on Jupiter and Saturn. Earlier this year I had some very good views of Jupiter, Saturn, and Mars thru a 36-inch F/3.5 from Cherry Springs ( one of the observers using the scope that night, and my Obsession 20 - was Al Nagler - who of course wanted to compare eyepieces! ).

I confess to not being very much of a "planets guy" -- mostly because of the poor seeing in the Northeast (jet stream - Great Lakes). However, I do 'try' at times - including imaging - with less than 'stellar success'.

I know that 'seeing is everything' when it comes to planets -- but that was more than confirmed about 3 years ago when I attended an evening "planet imaging workshop" presented at NEAIC by Christopher Go.

The target was Jupiter - and the Celestron reps were on hand to provide a brand-new-out-of-the-box C-11 EdgeHD, and their best planetary cameras, Barlow, connectors, etc. Roland and his crew were there to set up an Astro Physics 1100GTO mount for it all to ride on.

After capturing the data (with the precipitants getting copies) we all went inside and Chris spent about 2 hours going thru his usual processing methods - which precipitants were free to copy if they had a laptop and software.

The result -- pretty mediocre - in fact, not any better than what I usually do - from one of the best planetary imagers on the planet. He shrugged his shoulders and said "I guess this shows the difference in seeing between the Philippines and New York!" -- not to mention that planets can be near the zenith for him.

Back in the 1980's I had an ATM friend who wanted to "knock the planets right out of the sky" - so he made a 10-inch F/10 "Planetary Newt" to put on an old fashion alt/az ATM mount. He had made maybe 6 or more mirrors - so the optics were very good.

It actually worked pretty well on our few nights of good seeing. However, one night he fell off the ladder and broke his arm. After recovering - he cut the tube down and put an F/5 mirror in it. I don't know where that F/10 primary ever got to.

It's huge. I'm going to need to make a wheeled cart for the Meade RG mount, Something with big enough wheels for turf. I'll post a photo when I get home. My phone camera pic is too big to post on CN.

I have an 8" F/8 home-made Newt (traditional Parks tube, mirror by me, smallish secondary, etc). I've used it a few times side-by-side with an Astro Physics 6" F/12 triplet and an old Cave 8" F/6. Several of us could see no difference in the views of moon and planets in the 3 scopes. That was "many moons ago" so perhaps lack of experience was at play.

Late to the thread with my $0.02, but I'm with Redbetter in post #63. I typically experience exceptional seeing only a few times a year here in southern New England, but when the good skies do arrive my pedestrian XT8 provides some great planetary views: swirls in the belts and crisp transit shadows on Jupiter; clear, dark Cassini Division on Saturn, polar cap and reasonable surface markings on Mars. I suppose more powerful scope configurations would do better, but I find the old saw about "no substitute for good seeing" usually rules the night.